[Castor-users] Problem with sensitivity computed from normalization datafile

[Simon Stute]

Hi Julien,

Looking at the SensiNorm, you are taking normalization and/or 
attenuation into account, because we can see your object in the 
sensitivity image.
If you really want to disable it, even if it is present in your 
normalization data file, just use the "-ignore-corr attn,norm" option, 
as you did in the reconstruction.
Otherwise, the attenuation is still present in the sensitivity image, 
even if you ask for ignoring it in the reconstruction, as you provide 
the sensitivity image.
I suggest you try this, until you get an almost similar image to the one 
built with the scanner elements.

Also, when looking at the SensiNorm, it is quite noisy and we can see 
the inserts which looks like as if you used the prompt data as the 
normalization coefficients.
I am wondering what kind of normalization coefficients are you using ? 
Are you using the one provided by Philips ?

Best
Simon




Le 22/07/2018 à 17:18, Julien Salvadori a écrit :
>
> Dear Castor users,
>
> I can reconstruct without problem a list mode from an IEC phantom 
> recorded on the Philips Vereos TEP (with and without correction) when 
> the sensitivity is calculated from the .geom scanner. However, when 
> the sensitivity is generated from a normalization file, it does not 
> work anymore. I have no idea where the problem may come from, 
> especially since the sensitivity image generated from the 
> normalization file seems correct to me.
>
> Here in attachement :
>
> “SensiScan” : Sensitivity calculated from the scanner element without 
> taking into account attenuation and normalization.
>
> “ReconWithSensiScan” : MLEM reconstruction with sensitivity 
> “SensiScan” without any correction
>
> èGets reconstructed images which seems to me coherent considering the 
> absence of correction
>
> “SensiNorm”: Sensitivity calculated from the normalization datafile 
> without taking into account attenuation and normalization (attenuation 
> and normalization factor set to 1)
>
> ReconWithSensiNorm : MLEM reconstruction with sensitivity “SensiNorm” 
> without any correction
>
> èGets an almost uniform image with values very close to 0
>
> Do you think that the sensitivity image calculated with the 
> normalization file seems correct? Have you ever encountered a similar 
> problem?
>
> Any help will be welcome!
>
> Kind regards
>
> Julien Salvadori
>
> Phd student, IADI
>
>
> ​
>
> 1.zip 
> <https://drive.google.com/file/d/1oU9veGi2I5sE8fS0-aeutq0HsUeTFn-Y/view?usp=drive_web>
> ​
>
>
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